Engine starter



Feb. l?, R948, I D L MlLLER 2,435,355

ENGINESTARTER Filed ook. 15, 1945 2 sheets-sheet 1 I muy Feb. 17, 1948. D. L.. MILLER ,Y 2,436,365

ENGINE STARTER l y Filed Oct. 15, 1945 2 Sheets-sheet 2 u IN VEN TOIR.

WITNESS BY mzz J l E TTORNEY 190mb@ WZLZZW Patented Feb. 17, 1948 ENGINE STARTER Donald L. Miller, Pine City, N. Y., assigner to Bendix Aviation Corporation, Elmira Heights, N. Y., a corporation of Delaware Application October 15, 1945, Serial No. 622,331

9 Claims. 1

The present invention relates to engine starter gearing and more particularly to a drive of the automatically engaging type adapted to maintain operative connection until the engine is reliably self-operative.

It is an object of the present invention to provide a novel engine starter drive of the type above set forth which is efficient and reliable in operation, simple and compact in construction and adapted for economical manufacture.

It is another object to provide such a device in which a yielding member is used in the driving l connection, by which the load is progressively picked up.

It is another object to provide such a device which is adapted to connecte, starting motor to a member of an engine to be started and to maintain such connection as long as the starting circuit is energized.

It is another object to provide such a device which enables the engineto overrun the starting motor quietly and without danger of jamming.

It is another object to provide such a device which is dependent on the speed of rotation of the starting motor t-o keep the gearing engaged.

It is another object to provide such a device with a means of opposing the disengagement of the driving member until the starting motor begins to decelerate.

It is another object to provide such a device having two threaded members of diierent pitch; the member having the higher pitch thread serving to traverse a drive pinion into and out of mesh with an engine gear, while the member of lower pitch controls an inertia member to oppose demesh of the pinion.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing, in which:

Fig. 1 is a side elevation partly in section showing a preferred embodiment of the invention with the parts in idle position;

Fig. 2 is a similar View showing the parts in the positions assumed during the cranking operation;

Fig. 3 is a similar view showing the parts in the positions assumed when the engine starts and overruns the drive while the starting motor is still in operation;

Fig. 4 is a detail view in perspective of the differentially threaded drive shaft; and

Fig. 5 is a detail view in perspective of the inertia blocking member, the spacing ring and the control nut in disassembled relation.

2 In Fig. 1 `of the drawing, there is illustrated a power shaft I which may be the armature shaft of a starting motor not illustrated. The power shaft has a reduced extension 2 forming a shoulder 3, and an engine driving member 4 in the form of a pinion is slidably journalled on said extension for movement longitudinally into and I' out of mesh with'a gear 5 of an engine to be started, said shoulder forming a stop for dening the operative position of the pinion.

An actuating member in the form of a hollow sleeve 6 having a threaded portion I of low pitch, and a, second threaded portion 8 of higher pitch, is xedly mounted on the power shaft I by any suitable means such as a cross pin 9 retained by a spring ring I0. A blocking member in the form cf a nut I I is threaded on the portion 1 of sleeve S having a comparatively low pitch, and is retained by a thimble I2 which is adapted to enter a counterbore in the end of sleeve 6 and is anchored on power shaft I by the pin 9. Thimble I2 has a radial ange I3 which denes the normal position of blocking nut II, the forward movement of said nut being dened by a shoulder I4 at the end of thread 1.

A control nut I5 is threaded on the portion 8 of sleeve B having a comparatively high pitch, and is separated from said blocking nut by a spacing ring I6 which is journalledvon the rear of the control nut and held in place by a lock ring Il, The adjacent surfaces of the blocking nut and spacing ring are preferably formed with undulations or inclined abutments I8 and I9, respectively, in order to overcome any tendency of these members to wedge or stick together.

An elastic member in the form of a cylindrical rubber block 20 is seated on the control nut I5. bearing at one end against a radial iiange 2I of the nut and at the other end against a radial flange 22 of a thimble 23 which is mounted in telescopic relation with control nut I5. A barrel member or casing 24 is arranged to house the rubber block and is slidably journalled at one end on the flange ZI of the control nut, being retained thereon by an inturned lip 26. The other end of the barrel is provided with notches 21 adapted to receive radial lugs 28 on thimble notches 2l of the barrel and are held therein by lock wire 32 so as to connect said elements for rotation and longitudinal movement in unison. -A driven clutch member '33 having teeth 34 is in the control nut and pressed' against' the`V threaded sleeve 6 by means of-a spring ringii,

seated in a circumferential groove 43 in the :control nut. The sleeve 6 is preferably provided with an inclined shoulder 42 in position to 'beengaged" by the anti-drift ball 40 when the partsarein' idle position.

In-operation, when the starting motoris energized, the power shaft lrotates the screw sleeve therebyv moving-the control nut I5 forward on the high pitched thread 8, which motion is transmitted throughthe rubber block 2B, driving clutch member Zit-:spring-Y 35 anddriven clutch member 34to thepinion to-advancezthe pinion into mesh with the engine gear. It the teeth of the pinionshould abut againstthe ends of the engine gear teeth, the spring -35 will yield andpermit the clutch 29, 33 to close and index the pinion teethdnto -registry withthe tooth spaces of the enginegear, whereupon. said spring expands and snapsthe pinionforward, andthe meshing move.- ment proceeds. When the longitudinal'movement ofthe pinionis .arrested` by the shoulder. 3, further rotation ofpower shaft ltorques and compresses-the rubber cylinder 20 forcing the driving clutch member-2S .into engagement with the driven clutch. member .'53V and thereafter yieldably transmitting the rotation of the starting motor tothe pinionfllto crank the engine. At the same time, due to the rotation of the screw sleeve 6, the blocking nut- Il also moves forward-on the lowpitched threads 'l until it isstopped by the shoulder I4vat the end ofsaid threads. It is then in aposition tooppose demeshing movement of the control nut.

When the engine iires, the consequent acceleration of the pinion' is transmittedithrough the clutch 33,-29 and rubber block 2G tothe control nut, causing itto overrun the screw sleeve 6 and start back towardidle position, thereby permittingthespring 35 tofopen said clutch and allow the pinion to overrun. Since at this-time the drive'shaft I is also being accelerated by the starting `motor (although at a lower rate) due to the`l reliefof' the crankingv load` therefrom, the blocking nut ll'is rmlyheld'against the stop shoulder i4 in position to engage the spacing ringl i6 'and' thereby arrest the demeshing movement of the'control nut l5 as shown in Fig. 3. Any momentary tendency there might be for the control nut to frictionally pick up-and rotate the blo'ckingnut is obviated by making the pitch of the'threadsof the control nut higher than that of the' blocking nutl so that ii the nuts should attempt 4to rotatesin-unison on the screw shaft, they will approach eachother and'lock up.

Ii the engine should not continue to run, cranking will-be resumed as soon as'the pinion slows down to the speed of the starting motor, the spring 35` generating suicient friction to ensure the proper traversal of the controlnut. When the engineI isreliably: self-operative, the f operator deenergizes the starting motor whereupon the deceleration of the motor shaft causes both the blocking and control nuts to thread themselves back on the screw shaft to idle position.

Although but one embodiment of the invention has been shown and described in detail, it will be apparent that other forms are possible and changes may be made in the arrangement and proportions ofthe. parts without departing from the spirit of the invention.

What is claimed is:

l. In an engine starter, a motor shaft, a pinion slidably journalled thereon for movement into and out of meshwith an engine gear, means responsive` to acceleration of the motor shaft for movingthe pinion into mesh with the engine gear and thereafter yieldably connecting the pinion to rotate'with the motor shaft, a blocking member'movable longitudinally along the motor shaft, and means responsive to acceleration of the motor shaft for moving the blocking member into position yto hold the pinion mesh'with the' engine gear. Y

2. In an engine starter, a power shaft, aipinion slidably journalled thereon, a screw sleeve xed on the power shaft, means including a control nut threaded on the screw sleeve for moving the pinion into mesh with an engine gear andthereafter connecting the pinionV to'rotate with the power shaft, and a second nut threaded on the screwsleeve and movable by acceleration of the screw sleeve into position to` prevent demeshing the pinion.

3. An engine starter comprising a pcovershaft,l a pinion slidably and rotatablymounted thereon, a screw sleeve connected to rotate with the power shaft, means including a control nut 4threaded on the screw sleeve for moving the .pinion into mesh with a gear of an engine to be started, and thereafter connecting the pinion to rotate with the power shaft,.and a blocking nut on .the screw sleeve intandem relation with thecontrol nut and movable` by acceierationv oiy the screw. sleeve intothe path of movement of the control nut.`

4. In-an engine starter, a power shaft; a pinion slidably jcurnalled thereon, a screw sieevexed on the power shaft, means including a control nut threaded on the screw sleeve for moving thepinion into mesh with an engine gear and thereafter connectingthe pinion to rotate withthe power shaft, and asecond nutthreaded on the screw sleeve'and movable by accelerationof the screw sleeve into position to prevent demeshing the pinion, said second nut being traversed backward to permit demeshing of said pinion by deceleration of said power shaft.

5. In an engine startena power` shaft-an actuating memberxed thereon, adrivingmember slidably-journalled on the power shaft, means including a control member cooperating `with said actuating 'member for moving the driving member into and out of engagement withamember of an engine to be started,I said vmeansffurther including a i clutch between said control member and driving member; and a blocking member on the actuating member movable-.by acceleration of the actuating member-into Vposition to oppose disengagementy of thel'driving member fromv the engine member; including` iurther a spacing ring swivelled on the'control-member separating the blocking member from the control member.

6. In an engine starter, a Apower shaft; anactuating'member xed thereon, a driving .member slidably journalled on the power sha-it, means including a control member cooperating with said actuating member for moving the driving member into and out of engagement with a member of an engine to be started, said means further including a clutch between said control member and driving member; and a blocking member on the actuating member movable by acceleration of the actuating member into position to oppose disengagement of the driving member from the engine member, in which the actuating member is in the form of a screw sleeve, the control member and the blo-cking member being threaded on said screw sleeve in tandem.

7. In an engine starter, a power shaft, an actuating member fixed thereon, a driving member slidably journalled on the power shaft, means including a control member cooperating with said actuating member for moving the driving member into and out of engagement with a member of an engine to be started, said means further including a clutch between said control member and driving member; and a blocking member on the actuating member movable by acceleration of the actuating member into position to oppose disengagement of the driving member from the engine member, in which the actuating member is in the form of a screw sleeve having high and low-pitched threads, the control member and blocking member being in the form of nuts threaded on the high and lowpitched threads respectively, and said screw sleeve having a shoulder forming a stop for the blocking member.

8. In an engine starter, a power shaft, a pinion slidably journalled thereon for movement into and out of mesh with a gear of an engine to be started, means movable longitudinally responsive to acceleration of the power shaft for moving the pinion into mesh with the engine gear and thereafter connecting the pinion to rotate with the power shaft, said means including a clutch and means for closing the clutch by final longitudinal movement after the pinion is fully meshed, and opening the clutch when the pinion overruns the power shaft; and means responsive to-acceleration of the power shaft for preventing retrograde movement of the longitudinally movable means sufficient to demesh the pinion; said means for preventing retrograde movement being in the form of a blocking member and means responsive to acceleration of the power shaft for moving the blocking member into the path of movement of the longitudinally movable means.

9. In an engine starter, a power shaft, a pinion slidably journalled thereon for movement into and out of mesh with a gear on an engine to be started, means movable longitudinally responsive to acceleration of the power shaft for moving the pinion into mesh with the engine gear and thereafter connecting the pinion to rotate with the power shaft, said means including a clutch and means for closing the clutch by iinal longitudinal movement after the pinion is fully meshed, and opening the clutch when the pinion overruns the power shaft; and means responsive to acceleration of the power shaft for preventing retrograde movement of the longitudinally movable means suicient to demesh the pinion; said means for preventing retrograde movement being in the form of a blocking member and traversing means therefor, said traversing means operating responsive to deceleration of the power shaft to move said blocking member to idle position.

DONALD L. MILLER.

REFERENCES CITED UNITED STATES PATENTS Name Date Buxton Jan. 29, 1943 Number 

